The most concise comment would be that it simply doesn't seem to work most of the time, or at least the way it claims to.

1. Every time I attempt to connect to the "service" the messages "User Authentication failed." (This is displayed numerous times, every set of attempts, every day, often taking up to 10 minutes to finally connect.), "The L2TP-VPN server did not respond. Try reconnecting. If the problem continues, verify your settings and contact your Administrator." and "You were disconnected because the PPP server is not responding. Try reconnecting."
2. Often, after having the "service" running for a while, it disconnects itself.
3. Pure claims to have hundreds of servers in over 100 countries. However, supposedly different servers, in distinct cities in the countries, will have the exact same IP address.
4. When I first signed up, I could choose a city to be connected through, but Pure changed that. Now, only a country is displayed and Pure selects the city's server.
5. By default, the site selects the server in the country it wants--not what I want. If I don't make my own selection quickly, the country is set and I have to wait through all the connection and/or authentication failures until I can use the "service". Sometimes, even if I do get to choose the country, the site nevertheless connects to its own choice.
6. Most of Pure's servers are well known to sites so that, when I try to watch a video, the site knows I'm connected through a VPN and blocks me, just as if I were connecting from outside that country. Pure, if it cared, would regularly assign new addresses.
7. "Customer Service" is a long, drawn-out ordeal. Many times the rep doesn't understand the problem. Each one is apparently handling a number of multiple calls, so the response time is very long. A significant percentage of reps seem to be either bored or are arrogant. Once, when I asked an honest question about the service, the rep abruptly cut the call. Other times, it seems the "rep" is a computer robot.
8. The site is very difficult to access. To wit: affecting upgrades was not accessible from the page, so one had to go to the site's home page in another, new window. That seems to have been cleared up somewhat.
9. It costs more than other VPNs that offer the same or similar features, number of servers, etc. (After reading scores of reviews, promises and claims I fell for the hype and bought a "lifetime" subscription--good for 5 years and I have to remember to renew or it automatically self-cancels). At some point, possibly coming soon, I'll simply have to pony up more money to subscribe to a better VPN.

Given all the problems and obstacles I've experienced with Pure in just the 4 months I've subscribed, this is about as concise as I could be...